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Acute hemodynamic effects of digoxin alone or in combination with other vasoactive agents in patients with congestive
1College of Pharmacy and Allied Health Professions, Wayne State University, Detroit, Michigan.
Insights
Digoxin improves hemodynamics in congestive heart failure (CHF) patients with abnormal baseline measurements by increasing cardiac index and decreasing heart rate. Its effects differ in normal subjects and normalized CHF patients due to varied vascular responses.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Digitalis preparations, including digoxin, have a long history of use.
- Recent research focuses on the central hemodynamic and neurohumoral effects of intravenous digoxin in congestive heart failure (CHF).
- Digoxin's positive inotropic activity in vitro does not always translate to improved hemodynamics in humans.
Purpose of the Study:
- To investigate the hemodynamic and neurohumoral effects of intravenous digoxin in patients with congestive heart failure (CHF).
- To understand the differential effects of digoxin in CHF patients versus normal volunteers.
Main Methods:
- Intravenous administration of digoxin in patients with chronic CHF and abnormal baseline hemodynamic measurements.
- Comparison of effects in normal volunteers and CHF patients with normalized hemodynamics.
- Assessment of hemodynamic parameters including cardiac index, heart rate, and pressures.
Main Results:
- Intravenous digoxin increased cardiac index and decreased heart rate, left ventricular filling pressure, and right atrial pressure in CHF patients.
- Digoxin attenuated neurohumoral abnormalities in these patients.
- No significant hemodynamic influence was observed in normal volunteers or in CHF patients with normalized hemodynamics.
- Peripheral vascular effects, potentially vasodilation in CHF patients versus vasoconstriction in normal subjects, may explain differing responses.
Conclusions:
- Intravenous digoxin exerts beneficial hemodynamic and neurohumoral effects in specific CHF patient populations.
- The drug's efficacy is dependent on baseline hemodynamic status and potentially influenced by peripheral vascular responses.
- Further investigation is needed for specific CHF subtypes like diastolic dysfunction.
Abstract:
Although digitalis preparations have been in use for greater than 200 years, it is only within the last 2 decades that the central hemodynamic and neurohumoral effects occurring over several hours following intravenous administration of digoxin have been investigated in patients with congestive heart failure (CHF). Although digoxin has been shown to stimulate myocardial contractility in tissue preparations, its positive inotropic activity does not consistently translate into improvements in hemodynamic measurements in humans. Digoxin given intravenously results in increased cardiac index and decreased heart rate, left ventricular filling pressure, and right atrial pressure, as well as in acute attenuation of neurohumoral abnormalities, in patients with chronic CHF who have abnormal baseline hemodynamic measurements. Unlike other drugs with positive inotropic activity, however, digoxin does not influence hemodynamics in normal volunteers or in CHF patients in whom hemodynamics have been normalized with other therapies. These differing effects may be related to the drug's diverse peripheral vascular effects in CHF patients in whom vasodilation may occur in comparison with those that occur in normal subjects in whom the peripheral vasoconstrictor effects may prevent the inotropic effects of the drug from being translated into an increase in cardiac output. The hemodynamic effects of digoxin in patients with chronic CHF due primarily to diastolic dysfunction have not been fully investigated. Intravenous digoxin produces hemodynamic effects in patients with CHF associated with acute myocardial infarction, but these changes are small compared with those resulting from the administration of dobutamine. Digoxin does not appear to influence hemodynamic measurements in patients with right ventricular dysfunction unless concomitant left ventricular failure is present. In patients with chronic left ventricular dysfunction, the hemodynamic effects of intravenous digoxin and vasodilators are enhanced when these agents are given in combination.